1. Field of the Invention
The present invention relates to an additive composition suitable for use in the compounding of a granular detergent. More specifically, the present invention relates to an additive composition for a granular detergent, especially for a granular detergent containing an anionic surfactant, capable of providing an excellent soft finish or touch in fabrics to be washed, while simultaneously washing the fabrics during a fabric laundering operation.
2. Description of the Related Art
Heretofore, when fabrics are washed at home, softening is generally afforded after washing with conventional detergents and after rinsing with a large amount of water by treating the fabrics with a softening agent containing, as a main ingredient, a cationic surfactant such as a quaternary ammonium salt. The softening agent cannot be used together with detergents since, while cationic surfactants have excellent softening and antistatic effects, they do not result in a sufficient softening when used with detergents.
Home laundering detergents generally contain anionic surfactants. Cationic surfactants added to a laundering system are attacked by such anionic surfactants in the detergents. The quaternary ammonium salts lose their ionic properties and are stably dispersed in the laundering system. Therefore, it becomes difficult for the quaternary ammonium salts to be absorbed into the fabrics.
However, separate operations of laundering and soft finishing are troublesome and time-consuming. Accordingly, it is desired by consumers to develop a detergent composition capable of simultaneously washing and softening fabrics.
Hitherto, various attempts have been made to provide sufficient softening effects in fabrics by adding cationic surfactants to detergent solutions simultaneously during fabric laundering operations. For example, it has been proposed that cationic surfactants be granulated with inorganic or organic salts or organic dispersing retardants as disclosed in Japanese Examined Patent Publication (Kokoku) No. 36-8927, U.S. Pat. No. 4073735, and Japanese Unexamined Patent Publication (Kokai) Nos. 55-86895, 53-41312, and 49-98403.
Furthermore, it has been disclosed in, for example, Japanese Unexamined Patent Publication (Kokai) No. 59-6293, to use nonionic cellulose derivative in combination with cationic surfactants.
However, the softening effects in cotton fabrics are insufficient when cationic surfactants are granulated with inorganic salts although the softening effects in synthetic fiber fabrics are improved.
Furthermore, although the softening effects even in cotton fabrics can be obtained according to the softening method set forth in Japanese Unexamined Patent Publication No. 59-6293, the use of a large amount of the softening additives is required for obtaining the desired sufficient fabric softening effects and, therefore, a further improvement is desired from the practical point of view.